Field of the Invention
The present invention relates to a technology for detecting a subject image from an image and controlling zoom magnification.
Description of the Related Art
In the related art, there are imaging apparatuses that have a function of driving a zoom lens and performing optical magnification (hereinafter referred to as optical zoom) and a function of expanding a part of a photographed image and performing electronic magnification (hereinafter referred to as electronic zoom). The imaging apparatuses also have an automatic zoom function (automatic magnification) of automatically changing a zoom magnification according to detection information of subjects. Hereinafter, an optical zoom operation and an electronic zoom operation are collectively referred to as a zoom operation.
Japanese Patent Laid-Open No. 2012-95019 discloses the configuration of a camera equipped with an automatic zoom function of constantly maintaining the size of a subject. Japanese Patent Laid-Open No. 2012-95019 discloses a method in which a photographer selects a composition among a plurality of options, “face-up,” “bust-up,” and “whole body,” in an automatic zoom function. In automatic zoom control of maintaining the size of a subject image, the size of the subject image serving as a basis of zoom control is decided based on a selected composition. For example, when a photographer selects the composition “whole body,” a zoom operation is performed so that an image of the whole body of a person that is a subject fits in a photographing screen.
Japanese Patent Laid-Open No. 2011-188065 discloses a system in which a subject is tracked by an electric camera platform so that the subject fits at an angle of view and automatic photographing is performed by a camera installed on the electric camera platform. Japanese Patent Laid-Open No. 2011-188065 discloses a method of driving a zoom lens of a camera and searching for a subject when a subject is not detectable.
However, in Japanese Patent Laid-Open No. 2012-95019, when a subject which is a photographing target is far away, there is a possibility of the subject being undetectable even when the subject is within a screen in the above-described automatic zoom function. In such a scene, the automatic zoom function may not be performed based on subject information. Accordingly, in order to perform an automatic zoom process, it is necessary for a user to drive a zoom lens through a manual zoom manipulation until a subject image has a size at which it can be detected. However, convenience of the automatic zoom function of performing matching of an angle of view through a simple manipulation may be accordingly impaired. In a device disclosed in Japanese Patent Laid-Open No. 2011-188065, a zoom lens is automatically driven to search for a subject when a subject is not detected through tracking of the subject by the electric camera platform and the camera. However, there is a possibility of the search for the subject being ending when a subject which is not a photographing target is detected.